]> git.karo-electronics.de Git - karo-tx-linux.git/blobdiff - fs/jffs2/readinode.c
[JFFS2] fix buffer sise calculations in jffs2_get_inode_nodes()
[karo-tx-linux.git] / fs / jffs2 / readinode.c
index 717a48cf7df2aadbccde0432024dafde0e80a410..1298848336b8139e099eb51b757e34b610e9835d 100644 (file)
@@ -421,49 +421,38 @@ static inline int read_unknown(struct jffs2_sb_info *c, struct jffs2_raw_node_re
  *         negative error code on failure.
  */
 static int read_more(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
-                    int right_size, int *rdlen, unsigned char *buf, unsigned char *bufstart)
+                    int needed_len, int *rdlen, unsigned char *buf)
 {
-       int right_len, err, len;
+       int err, to_read = needed_len - *rdlen;
        size_t retlen;
        uint32_t offs;
 
        if (jffs2_is_writebuffered(c)) {
-               right_len = c->wbuf_pagesize - (bufstart - buf);
-               if (right_size + (int)(bufstart - buf) > c->wbuf_pagesize)
-                       right_len += c->wbuf_pagesize;
-       } else
-               right_len = right_size;
+               int rem = to_read % c->wbuf_pagesize;
 
-       if (*rdlen == right_len)
-               return 0;
+               if (rem)
+                       to_read += c->wbuf_pagesize - rem;
+       }
 
        /* We need to read more data */
        offs = ref_offset(ref) + *rdlen;
-       if (jffs2_is_writebuffered(c)) {
-               bufstart = buf + c->wbuf_pagesize;
-               len = c->wbuf_pagesize;
-       } else {
-               bufstart = buf + *rdlen;
-               len = right_size - *rdlen;
-       }
 
-       dbg_readinode("read more %d bytes\n", len);
+       dbg_readinode("read more %d bytes\n", to_read);
 
-       err = jffs2_flash_read(c, offs, len, &retlen, bufstart);
+       err = jffs2_flash_read(c, offs, to_read, &retlen, buf + *rdlen);
        if (err) {
                JFFS2_ERROR("can not read %d bytes from 0x%08x, "
-                       "error code: %d.\n", len, offs, err);
+                       "error code: %d.\n", to_read, offs, err);
                return err;
        }
 
-       if (retlen < len) {
+       if (retlen < to_read) {
                JFFS2_ERROR("short read at %#08x: %zu instead of %d.\n",
-                               offs, retlen, len);
+                               offs, retlen, to_read);
                return -EIO;
        }
 
-       *rdlen = right_len;
-
+       *rdlen += to_read;
        return 0;
 }
 
@@ -486,27 +475,9 @@ static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_inf
 
        dbg_readinode("ino #%u\n", f->inocache->ino);
 
-       if (jffs2_is_writebuffered(c)) {
-               /*
-                * If we have the write buffer, we assume the minimal I/O unit
-                * is c->wbuf_pagesize. We implement some optimizations which in
-                * this case and we need a temporary buffer of size =
-                * 2*c->wbuf_pagesize bytes (see comments in read_dnode()).
-                * Basically, we want to read not only the node header, but the
-                * whole wbuf (NAND page in case of NAND) or 2, if the node
-                * header overlaps the border between the 2 wbufs.
-                */
-               len = 2*c->wbuf_pagesize;
-       } else {
-               /*
-                * When there is no write buffer, the size of the temporary
-                * buffer is the size of the larges node header.
-                */
-               len = sizeof(union jffs2_node_union);
-       }
-
        /* FIXME: in case of NOR and available ->point() this
         * needs to be fixed. */
+       len = sizeof(union jffs2_node_union) + c->wbuf_pagesize;
        buf = kmalloc(len, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;
@@ -516,8 +487,6 @@ static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_inf
        if (!valid_ref && f->inocache->ino != 1)
                JFFS2_WARNING("Eep. No valid nodes for ino #%u.\n", f->inocache->ino);
        while (valid_ref) {
-               unsigned char *bufstart;
-
                /* We can hold a pointer to a non-obsolete node without the spinlock,
                   but _obsolete_ nodes may disappear at any time, if the block
                   they're in gets erased. So if we mark 'ref' obsolete while we're
@@ -533,32 +502,31 @@ static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_inf
                /*
                 * At this point we don't know the type of the node we're going
                 * to read, so we do not know the size of its header. In order
-                * to minimize the amount of flash IO we assume the node has
-                * size = JFFS2_MIN_NODE_HEADER.
+                * to minimize the amount of flash IO we assume the header is
+                * of size = JFFS2_MIN_NODE_HEADER.
                 */
+               len = JFFS2_MIN_NODE_HEADER;
                if (jffs2_is_writebuffered(c)) {
+                       int end, rem;
+
                        /*
-                        * We treat 'buf' as 2 adjacent wbufs. We want to
-                        * adjust bufstart such as it points to the
-                        * beginning of the node within this wbuf.
+                        * We are about to read JFFS2_MIN_NODE_HEADER bytes,
+                        * but this flash has some minimal I/O unit. It is
+                        * possible that we'll need to read more soon, so read
+                        * up to the next min. I/O unit, in order not to
+                        * re-read the same min. I/O unit twice.
                         */
-                       bufstart = buf + (ref_offset(ref) % c->wbuf_pagesize);
-                       /* We will read either one wbuf or 2 wbufs. */
-                       len = c->wbuf_pagesize - (bufstart - buf);
-                       if (JFFS2_MIN_NODE_HEADER + (int)(bufstart - buf) > c->wbuf_pagesize) {
-                               /* The header spans the border of the first wbuf */
-                               len += c->wbuf_pagesize;
-                       }
-               } else {
-                       bufstart = buf;
-                       len = JFFS2_MIN_NODE_HEADER;
+                       end = ref_offset(ref) + len;
+                       rem = end % c->wbuf_pagesize;
+                       if (rem)
+                               end += c->wbuf_pagesize - rem;
+                       len = end - ref_offset(ref);
                }
 
                dbg_readinode("read %d bytes at %#08x(%d).\n", len, ref_offset(ref), ref_flags(ref));
 
                /* FIXME: point() */
-               err = jffs2_flash_read(c, ref_offset(ref), len,
-                                      &retlen, bufstart);
+               err = jffs2_flash_read(c, ref_offset(ref), len, &retlen, buf);
                if (err) {
                        JFFS2_ERROR("can not read %d bytes from 0x%08x, " "error code: %d.\n", len, ref_offset(ref), err);
                        goto free_out;
@@ -570,7 +538,7 @@ static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_inf
                        goto free_out;
                }
 
-               node = (union jffs2_node_union *)bufstart;
+               node = (union jffs2_node_union *)buf;
 
                /* No need to mask in the valid bit; it shouldn't be invalid */
                if (je32_to_cpu(node->u.hdr_crc) != crc32(0, node, sizeof(node->u)-4)) {
@@ -596,7 +564,7 @@ static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_inf
                case JFFS2_NODETYPE_DIRENT:
 
                        if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_raw_dirent)) {
-                               err = read_more(c, ref, sizeof(struct jffs2_raw_dirent), &len, buf, bufstart);
+                               err = read_more(c, ref, sizeof(struct jffs2_raw_dirent), &len, buf);
                                if (unlikely(err))
                                        goto free_out;
                        }
@@ -616,7 +584,7 @@ static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_inf
                case JFFS2_NODETYPE_INODE:
 
                        if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_raw_inode)) {
-                               err = read_more(c, ref, sizeof(struct jffs2_raw_inode), &len, buf, bufstart);
+                               err = read_more(c, ref, sizeof(struct jffs2_raw_inode), &len, buf);
                                if (unlikely(err))
                                        goto free_out;
                        }
@@ -635,7 +603,7 @@ static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_inf
 
                default:
                        if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_unknown_node)) {
-                               err = read_more(c, ref, sizeof(struct jffs2_unknown_node), &len, buf, bufstart);
+                               err = read_more(c, ref, sizeof(struct jffs2_unknown_node), &len, buf);
                                if (unlikely(err))
                                        goto free_out;
                        }